Charge for fire extinguishers



Patented Oct; 7, 1930 UNITED STATES PATENT- OFFICE CHARLES A. THOMAS AND CARROLDA. HOCH'WAL'I', F DAYTON, OEIO CHARGE FOR FIRE EXTINGUISHEBS I No Drawing.

' This invention relates to fire extinguishers, more particularly of the portable type, and particularly to charges for. such extinguishers. r k

Portable fire extinguishers, as heretofore manufactured for many. years, have been generally of two types,-one type having some form of pumpmg mechanism for expelling the fire-extinguishing liquid, and the. other type having some form of chemical charge of such characteristics that during use chemical reaction will take'place to producea' gas eous pressure. for expelling the fire-extinguishlng liquid. This invention relates more 1 guisher, although it is in some aspects of more general application.

Of the latter class of extinguishers, that generally known as the soda and acid extinguisher 1s typical.

Such an extinguisher as heretofore generally manufactured has consisted of a casing containing a fire-extinguishing liquid, ordinarily a solution ofv sodium bicarbonate in water, a bottle of some acid, such as sul huric acid, beingv mounted within the contamer so that when the extinguisher is inverted for use the acid willescape into the carbonate solution and react therewith to. generate carto an extinguisher of this sOdiumT-bicarbona ution will not withstand very .low Qt'el npe tures of approximately 32" F. (depending upontthe concentratio 1of-1the bicarbonate 'j solution) the pcarbonate will precipitate out and th e mainextin'g'uishing-ll uid will then.

stand a temperature of -40 C. The ordinary soda and acid extinguisher has been dewriters;

particularly to I the latter form of extin- Another object of the invention is to probon dioxide which-in turn exerts a; pressure 'upon" theextinguishing solution to expel it from' the container. One plrincipal objection aracter is thatthe ratures. At tempera "February 1, 1926, for Antifreeze mixture for Application filed November 12, 1926. Serial No. 148,095.

ficient for certification on two grounds,first that the carbonate solution would freeze at a temperature much above that prescribed,

" One of the principal objects of this invention is to provide a fire extinguisher having a charge composed of materials which func- 0 tion with high efliciency of reaction to produce a discharge pressure at the low temperatureof 410' C. prescribed .by the undervide a charge for fire extinguishers of this character, comprising materials which are in liquid form, and are non-freezing at the low temperature prescribed by the under- Writers.

Another object of the invention is to provide such a charge, the constitutent materials of which are not only non-freezing but are chemically active at this low prescribed temperature.

Still anotherobject of the invention is to provide a freezing temperature depressant, for use in connection with the constituent materials within the extinguisher, which is chemically inert with respect to those constituents at least in so far as concerns gasforming reactions.

Still'another object of the invention is to provide as one constituent of a fire-extinguisher charge, a gas-generating material which when in solution contains for a given volume of solution a large capacity for gas formation.

Other objects and advantages of this invention will be apparent from the following description, and claims.-

This application is in part acontinuation of the app ication of Charles A. Thomas and Carroll A. Hochwa1t, Serial No. 85,386, filed fire extinguishers.

As stated above chemical reaction fire extinguishers as heretofore used have been incapable of use at the extremely low temperature of -40 0., which the Board of Nationhaving a freezlng point below al Fire Underwriters prescribes as a prerequi-' site for grantin an A-l rating upon a fire extinguisher. solution of calcium chloride in water will serve adequately as the main fire-extinguishing liquid, at such low temperatures, a calcium chloride solution C. But no constituents have been heretofore known which were chemically active at this low temperature, to react at such a rate in the production of a pressure gas as would make an extinguisher containing calcium chloride solution suitable. With a view to meeting the requirements of the Board of Underwriters and obtaining an extinguisher capable not only of withstanding a temperature as low as 4:O C., but also of operating at high efiiciency at that temperature we have, by searching and sustained experiments, ascertained that a compound contaning a sulfonic acid radical, such as a halogenated sulfonic acid, will not freeze at extremely low temperatures, will react with any carbonate, either solid, in solution or in suspension, to produce carbon dioxide.

Such a halogenated sulfonic acid is chlorosulfonic acid, ClSO OH, fluorosulfonic acid,

FSO OH, or, in fact, any sulfonic acid contaning any element of.the halogen group. Chlorosulfonic acid, which will not freeze at extremely low temperatures, is admirably adapted to act upon a solid carbonate, such as sodium bicarbonate, NaHCO to produce carbon dioxide with adequate efiiciency at temperatures much lower than 40 C. This reaction may be accelerated by water to which any non-freezing agent such as calcium chloride may be added.

It has been definitely ascertained that one molecule of chlorosulfonic acid acts with three molecules of sodium bicarbonate to produce three molecules of carbon dioxide, these agents resisting a temperature as low as 80 C.

An effective charge of'these non-freezing agents for expelling a gallon and a half of liquid from a fire extinguisher, consists of 8 ounces of sodium bicarbonate and 2 fluid ounces of chlorosulfonic acid.

While we have found sodium bicarbonate to be an efiective carbonate for reacting with chlorosulfonic acid to produce carbon dioxide at extremely low temperatures, any other carbonate, such as sodium carbonate, magnesium carbonate,potassium carbonate and am- .cont'aiiiing amonium carbonate may be used with a halonated sulfonic acid for this purpose with ghly satisfactory results.

- We have also found that other materials I sulfonic 'acid radical -SOADH) such, for example, as the sulonie acid of acetic acid, GH SOZOHCOOH,

willreact with a carbonate to space available insi e andother sulfonic acid radical containing produce carbon dioxide at extremely low temperatures. V

The sulfonicacid compound when used with a carbonate, not in solution, will react satisfactorilyat temperatures much below -40 C. However, the underwriters object to the use of a solid, or non-solution, form of carbon dioxide producting material. This is partly due to the fact that the reaction between the acid material and the solid carbonate material maybe non-uniform, and consequently may not generate a continuous gas pressure to effect uniform discharge of the fire-extinguishing liquid. Furthermore the solid carbonate material is apt to agglomerate into comparatively lar e lumps, which may acquire a hardened surface, so that the rate of reaction will be greatly slowed down due to the incapacity of the acid to contact with a large quantity of the carbonate material in a short time. Consequently it is extremely desirable, and almost commercially necessary, that the carbonate material be in solution. .However, all carbon dioxide producing materials heretofore used in fire extinguishers have been incapable of use at the low temperatures specified herein since they will freeze at those temperatures.

' For example sodium bicarbonate in solution is inadequate because it freezes at a temperature considerably above 40 Q. But we have discovered that ethylene glycol (CH (OH) when used with a carbonate in a water solution is chemically inert with respect to that carbonate, at least in so far as concerns any reaction which results in liberating the carbon the carbonate incapable of subsequent reaction with an acid to produce carbon dioxide, and is at the same time of such character that it will greatly lower the freezing temperature of such a carbonate in water.

Not only is this true but ethylene glycol being an uninflammable material lends 1tself nicely as an anti-freeze for the carbonate solution of the fire extinguisher. And a carbonate solution with ethylene glycol, with the water" and the carbonate and ethylene glycol admixed in suitable proportionswill have a considerably depressed freezing temperature. J 7

However, a carbonate solution containing sodium bicarbonate, or any of the'other usual carbonates, admixed with ethylene glycol is objectionable for use in a fire ex tinguisher, when used in a container se arate from may be lowered adequately, the volume of the resulting charge is so great that it occupies an undesirably lar portion of the total the extinguishenapld .e t e thus cuts down to an impracticable de which quantity of fire extinguishing liqui is to be expelled as a result ofthechemical the fire-extinguishing liquid, ecause even though its freezing temperature dioxide or rendering 1 reactions between this carbonate charge and acid charge. Of course the container could be filled wlth any suitable fire-extinguishing liquid such as a solution of carbonate in water with sufficient ethylene glycol admixed therew1th to produce the desired depression of the freezing point. At present, however, this is commercially undersirable because of the comparatively high cost of ethylene glycol which would make the use of it, in the large quantities needful for sufficiently lowering the freezing point of such a large quantity of carbonate solution as would constitute the main extinguishing liquid of the extinguisher, run the. cost of the charging materials for the extinguisher to a commercially unfeasible point. However, if it is desired to use ethylene glycol as a freezing temperature depressant in the main extinguishing -liquid, the extinguisher would work satisfactorily, with only the substitution of chlorosulfonic acid, or some analogous compound, in the place of the sulfuricacid ordinarily used in the soda and acid extinguisher, where extremely low temperatures are to be met.

However, such a carbonate as is ordinarily used in a fire extinguisher, for example sodium bicarbonate, is of such character that when placed in solution and used in a smaller separate container as described immediately above inorder that there may not be too great displacement of the main extinguishing fluid, there Will not be enough CO generated during the reaction with the acid from each unit volumn of carbonate solution to provide from such small volume of sodium bicarbonate solution sufficient expelling gas, and as a consequence where any of the ordinary used carbonates constitute the carbon dioxide producing material the quantity of carbonate producing solution in the charge is excessive. l/Ve have found, however, that sodium potassium carbonate (NaKCO is so constituted that when placed in solution in water the CO content per unit of volume will be quite high. Sodium potassium'carbonate is quite soluble in water as compared with other generally used carbonates such as sodium bicarbonate, approximately 185 parts of sodium potassium carbonate going into solution in 100 parts of water at 15 C. This compares with 35 parts of sodiumbicarbonate which will-go into solution into 100 parts of water at 15C.

Furthermore ethylen glycol when admixed with a solution of sodium potassium carbonate in water within a certain range of proportions will not only lower the freez ing temperature of that sodium potassium carbonate solution to below 40 (1., but in the proportion of 25% by weight of sodium potassium carbonate, 39% by weight of water and 36% by weight of ethylene glycol will form a eutectic mixture having a freezing point considerably below 40 C. Further-.

more these particular proportions afford the maximum weight of sodium potassium carbonate that will remain in solution with ethylene glycol in water at -40 C. And because of what may be called the CO concentration of the resulting solution the quantity of the solution necessary to produce the desired quantity of CO when compared with a solution of'an. ordinary carbonate such as sodium bicarbonate, is quite small; and consequently a commercially feasible chemical reaction extinguisher may be provided, active at 40 C., and having an adequate supply of fire-extinguishing liquid in the casing.

Of course if the volumetric capacity of the extinguisher permits, a lower percentage by weight of sodium potassium carbonate may be used which would merely mean increasing the quantity of carbonate solutionforming met, the relative proportions of the sodium potassium carbonate, the ethylene glycol, and the water may be varied as desired; for example 20% by weight of sodium potassium carbonate with 40% by weight of ethylene glycol and 40% by weight of water give very satisfactory results. But if the percentage of sodium potassium carbonate is increased ma-- terially above the 25% referred to above, then the Water and ethylene glycol would be relatively decreased accordingly, and the result would be a raisin of the freezing point.

For example, i the percentage of sodium potassium carbonate is increased to 30% by weight and the water and ethylene glycol 35% byweight of each, the freezing point would be above -40 (1, at which temperature some of the'sodium otassium carbonate will precipitate out of the ethylene glycol-water solution which will then freeze.

The most desirable results so far attained by us have been with a solution of the proportions producing the eutectic mentioned above,namely, 25% by weight of sodium potassium carbonate, 39% by weight of water, and 36% by weight of ethylene glycol.

Such a solution permits 0 a fire extinguisher having all the desirable characteristics that are resent when a material such as chlorosulfomcacid is used with a solid carbonat'e, and has in addition desirable characteristics that are not present when a solid with a solution of sodium potassium carbon- 7 ate combined with ethylene glycol as a freezing temperature depressant, satisfactory production of expelling carbon dioxide gas 'may be secured through the use of approximately 1.7 fluid ounces of chlorosulfonic acid gallons of fire extinguishing liquid, the carbon dioxide producing portion of the charge contains 14 ounces of water, 7' ounces of sodium potassium carbonate, and 11.3 ounces of ethylene glycol, to be used for reaction with 1.72 fluid ounces of chlorosulfonic acid. Such proportions will have a freezing point above the freezing point ofthe eutectic mixture specified above, but substantially below the prescribed temperature of 40 C.

While the invention has been described above particularly with reference to cholorosulfonic acid as the acid constituent of the carbon dioxide forming charge, reference is made primarily to this particular acid as one which functions ver satisfactorily, and is commercially availa le. However all the compounds secured from replacing the carbon atom normally attached to the sulfonic acid radical, in an organic acid com ound, or replacing a hydroxyl group similar y connected in an inorganic acid com ound containing-the sulfonic radical (-S 0H) will react with a carbonate with varying degrees of activity at varyin temperatures.

While the forms 0% invention herein de- .scribed constitute preferred embodiments thereof, it is to be understood that the invention is not limited to such recise forms, and that changes may'fbemad d therein without departin from thel scope of the invention which is efined injthejappended claims.

What is claimed is 1. A- charge for fire'ex-tinguishers, which comprisestwo normally separated portions, one of which consists of. an acid constituent chemically active; at temperatures as low as 40 6., the otherof. which comprises a solution .of a'se'cond constituent adapted to react with said first constituent to generate gas but normally freezing "at a highertemperaturejthan -40 0., and a freezing temperature depressant comprising a glycol in said'solution and chemically inert with re-' spect thereto for loweringthe freezingpoint of said solution.

2. A charge for fireqextmguishers, which comprises two normally separated portions,

-;one of which consists of a compound containing a sulfonic acid radical, and the other of which consists of a solution of a carbonate, admixed with ethylene glycol to lower the freezing'point thereof.

4. A charge for fire. extinguishers, which comprises two normally separated portions, one of which consists of a compound containing a sulfonic acid radical, and the other of which consists of a water solution of a carbonate, admixed with ethylene glycol to lower the freezing'point thereof.

, 5. An anti-freeze mixture for fire extinguishers, consistingrof ethylene glycol and a carbonate in a water solution.

6. An anti-freeze mixture for fireextinguishers, consisting of ethylene glycol and :odium potassium carbonate in a water soluion. 7

7. An anti-freeze mixture for fire extinguishers, consisting of sodium otassium carbonate by weight 25%, water y weight 39% and ethylene glfycol by weight 36%.

8. A charge for re extinguishers, comprising a carbonate solution of high carbon dioxide concentration, and a freezing temperature depressant chemically inert with respect to carbon dioxide producing reactions with said carbonate solution, comprising ethylene glycol.

9. A charge for fire extinguishers, which includes a water solution of sodium potassium carbonate containing a freezing temperature depressant which is chemically inert with respect thereto.

10. A charge for fire extinguishers," which includes a eutectic mixture of water, sodium potassium. carbonate, and a freezing tem-- perature depressant which is chemically inert with respect thereto. J

11. A charge for fire extinguishers, which includes a eutectic mixture ofwater, sodium potassium carbonate and ethylene glycol.

12. charge for lire extinguishers, which comprisestwo normally separated portions, one of WhlCh comprises a compound containing a sulfonic. acid radical and the other of which consists of a solution of sodium potassium. carbonate containing ethylene glycol to lower the freezin point thereof.

13-. A charge for re extinguishers, which comprises three normally separated ortions one of which consists of a water so ution o a freezin temperature depressant, said solution jbemg no freezing at very low temperatures andb adapted to serve as a fire extinguishing liquid, the other two of which are normally separated gas-generating portions consisting of a constituent having a sulfonic acid radical, and asolution 5 of sodium potassium carbonate contalmng achemically inert freezing temperature depressant therein. I a Y 14. A charge for fire extinguishers, which comprises an acid constituent a solution of a carbonate constituted to liberate w an expellingjgas on reaction with said acldconstituent, said acid andsaid carbonate solution being chemicallyactive. with respect to each other to produce such expelling gas 1' at temperatures ranging downwardly from substantially 0 (1., and a glycol inactive to efiect gas generating reaction with said carbonate solution for lowering the freezing point of the solution of said second'constitw.

cut.

. 15. A charge for fire extinguishers, which comprises three normall se arated portions, one ofvwhich consists o a e'extinguishing liquid which is non-freezing'at low temperaggtures, the other two of WhlCh are normally separated gas-generating portions consisting of an acid constituent and a solution of a carbonate constituted to liberate an expelling gas on reaction with said acid constituent, said acid and said carbonate solution being chemically active with respect to each other to produce such expellin gas at low temperatures ranging downwar ly from substantially 0 C. and which solution nor- 5 mally freezes at a temperature above said low temperatures, and a glycol-in said solution chemically inert with r ect thereto. a

16. A fire extinguishing liqui comprising a gas generating water solution includin 'a 40 compound of an alkali metal element hav ng high fire extinguishing properties at low temperatur'es and containing a glycol therein. w 17. A fireextinguishing liquid'c'omprisingf I a gas generating water, solution"liincludingia" compound of" potassium and i'containing '.18, glycol therein. v

;18'. vA charge for fire extinguishers having normallyseparated generating portions, comprising a'gas generating watersolntion including a: compound ofpotfissiumyandian acid compound containing a'- sl'llfonic ajc'zid-fi". 7 d l r: v 19. The use in a fire extinguisher of a wa- C- tersolution of sodium otassiumcarbonate I I containing in excesso 15% by'weight of sodium potassium carbonates. i; v. 20. A fireextinguis'hingl charge-com ris mg a-glycol mixed with a 'quid aving igh fire extinguishing properties at low tempera-- 60 tures and chemically inert with respect 'thereto.- I v. In testimony whereof weflhereto afiix our CHARLES Al -THOMAS. 66 CARROLL A. HOCHWALT. 

